I have a question about DCS3700's Enhanced Power-Loss Data Protection:
according to Intel DCS3700 spec: Enhanced Power-Loss Data Protection will save all cached data in the process of being written before shutting down.
So here is the question:
Imagine this case , if host send several write cmd to ssd and ssd compelete some cmd with returning fis ok. In the process of one write cmd, the ssd shuts down without returning fis ok to the host.
Note that all data of the acknowleged cmd and part of data of un-acknowleged cmd are in the ssd's cache.
The question is : according to Enhanced Power-Loss Data Protection, if all cached data will be written to flash, will s3700 make sure the un-acknowleged cmd data still valid?
Hello 火腿加小鸡,You're correct. As long as it was captured in the temporary buffers, it should be saved to the NAND, regardless of the status of the command.During an unexpected power loss or "unsafe shutdown" this feature allows the firmware routines in the SSD to respond and make sure both user and system data in the temporary buffers are transferred to the NAND media.Additionally, given the energy provided by the capacitor elements and urgency to recover data, firmware de-prioritizes non-essential controller activities to quickly get into data saving mode, with no impact to overall system performance."How Power-Loss Data Protection is Implemented The Intel SSD DC 3700 Series contains hardware- and firmware-based power-loss data protection features. The SSD includes a power-fail detection circuit, which sends a signal to the ASIC controller in the SSD indicating there is an imminent drop in power level. Triggered by this, SSD firmware disconnects the input power from the SSD. The SSD then relies on its on-board power-loss protection capacitance to provide enough energy for the SSD firmware to move data from the transfer buffer and other temporary buffers to the NAND."- http://download.intel.com/newsroom/kits/ssd/pdfs/Intel_SSD_DC_S3700_Product_Brief.pdf Intel® Solid-State Drive DC S3700 Series - Product BriefPlease let us know if this answers your question.Best regards,Carlos A.
But I still want to know that, how do you test this pattern?
Because our team is going to make a product with intel DC series, but we do not have test method to check if it behave as you said.It will be more helpful if you can provide us some test method.
As you know, if we need to check wether all cached data is written to nand, we need a method to cut ssd power in the process of a SATA write cmd.
I wonder if we need to write sata driver by ourself in Linux, or is there any ready-made application or software can help ?